Ceramic honeycomb substrates are widely used as anti-pollutant devices in the exhaust systems of automotive vehicles, both as catalytic converter substrates in automobiles, and as particulate filters in diesel-powered vehicles. In these applications, ceramic honeycomb substrates are formed from a matrix of thin, porous ceramic walls which define a plurality of parallel, gas conducting channels. In honeycomb structures used as ceramic catalytic substrates in automobiles with gasoline engines, the gas conducting channels are open at both ends. A catalytic coating is applied to the outer surfaces of the walls. Exhaust gases, flowing through the channels, come into contact with catalytic coatings on the surfaces of the walls. These substrates are referred to as flow-through substrates. In diesel systems, exhaust gasses also come into contact with catalytic coatings on the surfaces of the walls. In diesel applications, ceramic honeycomb substrates also have end-plugs in alternate gas conducting channels to force exhaust gases to pass through the porous channel walls in order to capture and hence filter out soot and ash particulates prior to exhaust discharge. These substrates are referred to as ceramic wall-flow particulate filters and more specifically as diesel particulate filters.
Improving the performance of ceramic wall-flow substrates for treating engine exhaust gases through the use of ceramic honeycomb substrates having catalytic wall coatings to reduce polluting hydrocarbon and/or nitrogen oxide emissions is desirable. Improving methods of manufacturing these substrates is also desirable. And, providing improved parts using improved methods of manufacture are also desirable.